Biden crossed the Democratic Party threshold of 1,968 delegates with a win in the primaries in Georgia, which was critical to his win in the general election in 2020. Trump won the Republican Party primaries in Georgia as well but will have to wait for results from the three other states that held their primaries on Tuesday -- Hawaii, Mississippi and Washington -- to clinch the nomination.

Neither of them faced a real challenge for their respective party nominations although the Republican primaries had remained open till March 5 when Nikki Haley, the former Ambassador to the UN, suspended her campaign leaving Trump the only one in the field.

In an election system typical to the US, aspirants to the White House need to win enough delegates -- every state primary or caucus grants them a certain number of delegates -- who will officially anoint their nominees at their party conventions later in the year. But the Biden versus Trump presidential election gets technically underway on Tuesday night.

Biden cleared the 1,968 delegates on Tuesday and Trump will have his 1,215 by the end of the day.